This invention relates to smoking articles such as filter cigarettes, and in particular to such smoking articles having means for adjustable air dilution.
Cigarettes having adjustable regions have become subjects of increasing interest, particularly in situations wherein the adjustment of the air dilution value of filter cigarettes is desired. Known methods for providing adjustments to the air dilution value of filter cigarettes generally involve making one or more openings through a substantially air impermeable filter plug wrap, through the substantially air impermeable tipping paper and through a corresponding sleeve which is placed over the tipping paper, which sleeve is movable either rotatably or axially in order to select the degree to which the sets of openings are in registry.
Numerous known methods for providing adjustments to the air dilution value of filter cigarettes suffer from various problems. For example, a movable sleeve may be easily inadvertently removed from the cigarette by the smoker and not readily replaced. Furthermore, the degree of registry between the sets of openings can be inadvertently destroyed by slight axial movement of the sleeve. Accordingly, the air dilution value, once set by the smoker, is not insured to any degree of consistency.
Recently, as disclosed in U.S. Pat. No. 4,532,943, a filter cigarette comprises a filter plug having a mouthend segment and a tobacco rod end segment, wherein the two segments are axially connected for rotation about the longitudinal axis of the cigarette. Typically, in such a filter, the two segments are defined by a circumferential cut in the filter plug. However, a cigarette having a means for adjustment which does not require a segmented filter for rotation is clearly desirable.
It would be highly desirable to provide a filter cigarette having a longitudinally adjustable filter region, said filter region being easily settable and capable of having unlimited rotational ability. In addition, it would be highly desirable to provide a filter cigarette having an adjustable filter region, which cigarette is relatively easy to manufacture at a commercial scale.